Iran's "supreme leader", Ayatollah Ali Khamenei, issued a stark warning to the US in a speech broadcast live on state-run radio this Sunday

The most significant threat he made was that oil shipments from the Gulf region would be disrupted if the United States attacked the middle-eastern nation.

"If you make any mistake (invade Iran), definitely shipment of energy from this region will be seriously jeopardized. You have to know this," Khamenei said.

He added that if there was a disruption, the United States and its allies could not secure all the oil shipments that transit close to Iran's coast. Much of the world's oil supply passes through the strategic Strait of Hormuz, which links the Gulf to the Indian Ocean and separates Iran from the Arabian Peninsula.

"You will never be able to protect energy supply in this region. You will not be able to do it," he said, addressing the West.

Khamenei, however, did not specify how oil supplies would be disrupted and insisted Iran would not start any war.

"We won't be the initiator of war," he said.

Western nations recently brokered an incentives package to persuade Iran to halt its uranium enrichment program. If Tehran refuses, the nations threaten U.N. sanctions.
But in todays speech Khamenei reiterated that Tehran is sticking to its postion that Iran rejects any such package that is conditional on the country first giving up its right to produce nuclear fuel. The United States and other Western nations suspect Iran's nuclear program is intended to produce weapons. Tehran insists it is only for generating electricity. But the ayatollah insisted that Iran has no interest in developing a nuclear weapons capabilty as Western powers fear.

Iran is the world's fourth-largest oil exporter and second-biggest power within the Organization of Petroleum Exporting Countries. Until now Iranian officials had repeatedly ruled out using oil as a weapon in the nuclear standoff with the West.

The supreme leader's harsh rhetoric came a day after President Mahmoud Ahmadinejad said a breakthrough in negotiations over Tehran's contentious nuclear program was possible and welcomed unconditional talks with all parties, including the United States.

Ahmadinejad said late Saturday his government would not rush to judge the incentives package.

And Khamenei appeared to be enforcing this tougher line today.

"That a country has no right to achieve proficiency in nuclear technology means it has to beg a few Western and European countries for energy in the next 20 years," he said. "Which honest leader is ready to accept this?"

These statements came as a top deputy at Iran's Supreme Security Council outlined in an interview the reasons that Iran wants a nuclear energy program and is looking for compromise with Western powers intent on hindering the effort.

Both men's remarks appeared to be part of an orchestrated effort by Iranian officials to keep open the possibility of talks with the United States. Ahmadinejad's comments Saturday came first on state-run television during a report about a phone conversation with UN Secretary General Kofi Annan. Ahmadinejad elaborated that night during a speech marking the anniversary of the death of Ayatollah Ruhollah Khomeini, the republic's founder.

Javad Vaeidi, a top deputy at Iran's Supreme Security Council, spoke emphatically during an interview Saturday about Iran's interest in peaceful energy. As Ahmadinejad did, Vaeidi said Iran wants to preserve its right to develop nuclear energy.

"We do not need a bomb," Vaeidi said. "We are a regional power now. We have security without a bomb. ... The bomb would cause us to lose our power because other countries in the region would then pursue it."

The U.S. demand to halt nuclear activity so talks could begin, is seen as a "humiliation" because Iran has the right under current treaties to a nuclear program.

The deputy chief of international affairs, was most clear when responding to questions about Iran's nuclear ambitions. He said Iran does not want to be a nuclear power for warlike purposes. Nuclear energy has become a global business, he said, and Iran wants to preserve its interests.

"They want to prevent us developing a nuclear industrial program in Iran but they are willing to sell us this product," he said about a previous debate over whether Iran could buy enriched uranium from the West. "It's business."

Vaeidi also said that achieving a nuclear bomb would not be in Iran's interest for other reasons: Iran wants stability and to attract investors. And pursuing nuclear weapons would only legitimize Israel's existing nuclear program.

"It would also mean the United States would increase its military presence and influence in the region," he said.

"Iran is looking for compromise and we are trying to restart talks. This is the reality," Vaeidi said. "We're not after confrontation. We're not after adventure. We're not after conflict."